Method of printing on vesicular material



July 25, 1961 R. H. KAY

METHOD OF PRINTING ON VESICULAR MATERIAL 2 Sheets-Sheet 1 Filed Sept. 12, 1958 INVENTOR. RONALD H. KAY

ATTORNEY July 25, 1961 R. H. KAY 2,993,805

METHOD OF PRINTING ON VESICULAR MATERIAL Filed Sept. 12, 1958 2 Sheets-Sheet 2 United States Patent U 2,993,805 METHOD OF PRINTING ON VESICULAR MATERIAL Ronald H. Kay, Palo Alto, Calif., assignor to International Business Machines Corporation, New York, N.Y., a corporation of New York Filed Sept. 12, 1958, Ser. No. 760,645 1 Claim. (Cl. 117-62) The present invention relates in general to methods of printing and rel-ates more particularly to methods for printing on vesicular material.

The use of vesicular materials in so-called scatter photography for the storage of images of different documents and the like is well known. Vesicular materials are materials which are capable of producing an image when they are irradiated With selected radiation, usually ultraviolet light, and then heated to at least a predetermined temperature. Most of such vesicular materials comprise a vehicle or hinder which is impregnated with a light sensitive diazonium salt which decomposes when exposed to light to evolve nitrogen gas. This nitrogen gas is generally in the form of small bubbles which form the latent image in the material. Upon heating of the material, the smaller bubbles expand to produce larger bubbles which form light scattering centers to produce the image. Once the smaller bubbles have expanded into the larger bubbles the image thereby formed becomes irreversible and permanent. The vesicular material may be either transparent, in which case the irradiation and heating cause selected areas of the material to turn opaque, or the material may be opaque, in which case the irradiation and heating produce a Whitening in the selected areas. The vesicular materials are generally available in the form of sheets having a layer of vesicular material bonded to a sheet of backing material, either transparent or opaque.

These vesicular materials have heretofore been utilized by first selectively irradiating the material in the pattern of the image to be formed on the material, such as through a stencil or film negative, to form a latent image of the pattern in the vesicular material. The irradiated material is then heated to enlarge the latent image bubbles forming the pattern, thus producing light scattering centers which cause the material to turn opaque or which refleet incident light in the image area, to produce a permanent and irreversible image. This method is suit-able for the photo-reduction of documents and the like, where there is a considerable amount of information to be recorded for each image, but where there is only a relatively small amount of information and/or this information is to be changed frequently, the above method has the disadvantage of requiring that a different stencil or negative be made for each change of information.

The present invention is directed to a method of utilizing vesicular material by first generally irradiating the material to substantially unin-formly expose the entire vesicular material to the radiation. After this general irradiation, the material is selectively heated in a pattern or configuration corresponding to the information to be recorded, to thus selectively produce an image on the vesicular material according to the configuration of the heated portion thereof.

While it is Well known in the prior art to use heat sensitive printing media for recording and other purposes, the present invention differs from these prior art methods in utilizing essentially a two-stage printing process requiring both the general irradiation of the vesicular material and then the heating of selected portions of the vesicular material in accordance with the infomiation to be recorded. By virtue of the two-stage process utilized in the present invention to produce a permanent image on the material,

7 2,993,805 Patented July 25, 1961 it is possible to alternately print on separate areas of the same sheet of vesicular material by selective exposure to light followed by general heating or general exposure to light and selective exposure to heat. That is, one portion of a sheet of vesicular material may be printed by means of selective exposure to radiation followed by general heating of this portion, while another portion of the sheet may be printed by general exposure to radiation followed by selective heating.

The present invention may be utilized in a number of ways in producing a permanent image on a vesicular material. As one example, the present invention may be utilized in conjunction with the printing of document images on transparent vesicular material to print some type of information relative to the documents. In this application, images of the documents or other papers to be stored are projected onto a predetermined portion of the vesicular material by means of the selected irradiation. Either prior to, simultaneously with, or subsequent to this projection, another portion of the sheet is generally exposed to the irradiation. Thus, the sheet of vesicular material has on one portion thereof the latent images of the documents to be stored, and has on another portion thereof a band which has been generally exposed to the radiation but which has no latent image thereon. The separate portions of the sheet may then be heated, either sequentially or simultaneously. The portion which has the latent images of the documents is heated over its whole general area, to fix the latent images present in the vesicular material. The portion of the material which has been generally exposed to irradiation is selectively heated by means of a heated element having a configuration corresponding to the information to be printed, to produce printing on this portion corresponding to the configuration of the heated element.

As another example, the method of the present invention may be utilized to provide machine reada-ble representations or marks on a sheet of vesicular material, either transparent or opaque. In this application, a sheet of vesicular material may be first generally exposed to selected radiation, and then the irradiated vesicular sheet may be selectively contacted by heated elements which produce localized heating of selected portions of the sheet to produce a visual mark or indicia at these selected portions. In one embodiment, the sheet of vesicular material may be in the general shape of a conventional business machine card and the heated elements contacting the vesicular material may be the heated punch bars of a punch normally utilized to provide coded openings in a business machine card, but which in the present application are adapted to just contact the surface of the vesicular material to provide a localized heating corresponding to the general area of the punch. Thus, the sheet has produced thereon selectively positioned visual marks which may be subsequently optically read by a machine for sorting or other operations which may be performed with the sheet.

It is therefore an object of the present invention to provide improved methods and apparatus for printing on vesicular material and particularly on transparent vesicular material.

It is a further object of the present invention to provide improved methods and apparatus for printing on vesicular material in which the material is first generally exposed to irradiation and then the irradiated material is selectively heated in accordance with the configuration of the information to be printed.

Objects and advantages other than those set forth above will be apparent from the following description when read in connection with the accompanying drawings, in which:

FIG. 1 diagrammatically illustrates one embodiment of the present invention in which the selective heating of the irradiated vesicular material is accomplished with a heated printing roller;

FIG. 2 diagrammatically illustrates an alternative embodiment of the present invention in which the selective heating of the irradiated material is accomplished with heated bars which contact the surface of the irradiated material; and

FIG. 3 diagrammatically illustrates a further embodiment of the present invention in which sheets of vesicular material have printed thereon images from a photo-image reduction apparatus and which also have information printed thereon by means of selective heating of the material.

Referring to FIG. 1, reference character 11 designates generally a sheet or card of vesicular material which is to be printed in accordance with the present invention. As indicated heretofore, sheet 11 may be of any suitable vesicular material which has the property of forming light scattering centers by means of bubble formation in response to irradiation by selected illumination, followed by heating of the irradiated area of the material. one of such materials which I have found satisfactory for the purposes of the present invention is sold under the trademark Kalvar. An example of this material and the techniques involved in its processing are described in a paper entitled The Kalfax System of Microfilm Duplication, by Floyd T. Neth, Proceedings of the National Microfilm Association, 7th Annual Meeting, April 21-23, 1958, pages 27-40. In the illustrated embodiment of FIG. 1, sheet 11 is generally in the shape of a standard business machine card, and as such may be adapted for use in business machine systems.

Assuming that it is desired to produce printed information on a top portion 12 of card 11, the card is first exposed to suitable radiation, such as that produced by an ultraviolet source indicated generally as a lamp 13. The illumination from lamp 13 passes through a slit 14 in a masking member 16, the long dimension of slit 14 corresponding to the width of the portion 12 of the card on which the printing is to be produced. The entire length of portion 12 may be exposed to irradiation simultaneously, or as in the embodiment illustrated in FIG. 1, card 11 may be carried by suitable means such as a belt 17- which moves card 11 under mask 16 and slit 14 so that A the portion 12 is sequentially exposed along its length to irradiation from source 13. The radiation from source 13 produces a plurality of small bubbles in the portion 12 of the vesicular material, by virtue of the gas evolution mechanism discussed above,

After the irradiation from source 13, the irradiated portion of the card has heat applied thereto in a configuration corresponding to the information to be printed. In the embodiment illustrated in FIG. 1, such heating is done by means of a heated printing roller or member 21 which is driven by a shaft 22. Roller 21 may bear any suitable printing indicia corresponding to the information to be printed on card 11, and in the illustrated embodiment such indicia is in the form of digits formed by raised portions of roller 21. Roller 21 is heated by any suitable means, shown diagrammatically as a heating coil 23 disposed adjacent the outer surface of roller 21 so as to heat the raised digit-bearing portion thereof. Heating coil 23 may be energized from any suitable electrical circuit (not shown) through conductors 24 extending out of shaft 22.

As card 11 is carried along by belt 17, it passes under roller 21, as shown by the position 11, so that the portion 12' thereof lies under roller 21. The information to be printed on portion 12' of the card may be disposed on roller 21 in sequential form, so that the roller may be merely rotated as card 11 passes thereunder to print the desired information on the card. Alternatively, suitable indexing means may be provided for lifting and ro-' tating roller 21 to print any selected combination of digits, numerals, or other symbols on portion 12'. As the heated, raised characters of roller 21 contact portion 12, the heat causes the smaller bubbles produced by the prior irradiation to expand, thus producing light-scattering centers in the region contacted by the heated printing mechanism. Portion 12' thus has permanently printed thereon the information carried by the heated printing element, such as the digits shown in the embodiment of FIG. 1.

FIG. 2 illustrates an alternative embodiment of the present invention in which machine-readable information is printed on a vesicular material in accordance with the present invention. In FIG. 2, a sheet or card of vesicular material 31 is exposed throughout substantially its entire Width to radiation from an ultraviolet source 33 through a slit 34 in a mask 36. Card 31 is carried along by belt 17 so that the entire length of card 31 passes under slit 34 to sequentially irradiate substantially the entire length of the card. After this irradiation to produce a plurality of bubbles in the vesicular material of card 31, the card next passes under a device for selectively heating areas of the irradiated material in accordance with the information to be printed thereon. Such heated printing means may be in the form of a plurality of heated bar members 38a, 38b, etc. which are adapted to be selectively moved to just contact the surface of the moving card 31,

Bars 38a, 38b, may be heated by any suitable means, such as a heating coil 39 disposed in the bar housing so as to heat the bars to the required temperature. Bars 38a, etc., may be of any suitable type, and may for example be of the type utilized to punch rectangular openings in conventional business machine cards. In this case, such a punch could be modified by the addition of heating coil 39 and by shortening the stroke of the punch bars so that they just contact the surface of card 31, rather than penetrating therethrough as in the case of the punching of conventional business cards.

As the selected bars 38 are actuated downwardly to contact card 31, the heated bar produces an enlargement of the bubbles in the vesicular material of card 31. This heating causes the vesicular material to produce lightscattering centers in the contacted area to form an image or reproduction on card 31 of the configuration of the heated surface. Bars 38 thus produce on card 31, as shown by card position 31, a plurality of marks 38, with the position of these marks corresponding to the position of the actuated heated bar. These marks 38' may then be utilized in some manner, such as by photo-electric scanning of the cards for sorting or other operations normally done with conventional business machine cards.

FIG. 3 illustrates an additional alternative embodiment of the present invention for producing a sheet having a plurality of photo-images of documents to be stored, together with human readable marks on the sheet indicating the nature of the stored documents. In the embodiment of FIG. 3, a sheet 41 of vesicular material has a portion 43 which receives the photoimages to be recorded, and has another portion 42 on which is recorded information concerning the photo-images. Cards 41 may be fed to the illustrated apparatus from a stack by means of a wheel 40 which sequentially directs cards 41 onto a belt 44.

The documents to be recorded on cards 41 may be in any suitable form, such as the reduced images of documents contained on a reel of film 46. Film 46 is adapted to be fed over a masking element 47 having a plurality of openings 47a therein which establish communication between card 41 and a plurality of ultraviolet light sources 48a, 48b, 480. The light from sources 48a, 48b, 48c is projected downwardly through film 46 and openings 47a through a suitable lens system (not shown) to focus the images of the documents from film 46 on card 41. In the illustrated embodiment, it is assumed that there are three masking openings 47a and three ultraviolet sources 48a, 48b, 48c, and that these sources may be selectively energized to control the creation of latent images 50 under the different masking openings. These projected images on card 41 produce in the card a plurality of latent images 50 of the projected documents by means of the formation of small bubbles in the vesicular material, as discussed above. The latent images 50 may be of the same size as the reduced images on film 46, or the latent images may be further reduced with respect to the images on film 46 by means of a suitable lens system.

*Card 41 next passes under suitable means for generally heating the portion 43 to develop the latent images 50. Such heating means may be a heated roller 52 which rolls over the portion 43 of card 41. Roller 52 may be heated by any suitable means such as a heating coil 53. As the heated roller 52 passes over the latent images 50 on card 41, the bubbles in the vesicular material expand and become fixed, to produce a permanent image of the documents, as represented by images 50".

After production of the images of the documents to be stored on portion 43, the card may next be processed in accordance with the present invention to provide a representation thereon containing information concerning the stored documents. Since the photo-images 50 on card 41 are generally too small to be legible to the human eye, card 41 preferably has provided thereon some human-readable indication or representation concerning the stored documents. This indication may be of any suitable type, such as a digit or character, indicating the nature of the stored document.

To pnovide this information or representation, the upper portion 42 of card 41 may be first generally exposed to ultraviolet radiation from a source 56 through a masking device 57 to irradiate the portion 42 of the card. The irradiated portion 42" then passes under a device for selectively imprinting the information on the irradiated portion 42". Such device may, for example, be a wire printer device 58, in which a plurality of wires are selectively positioned to form diflerent letters, numerals or other characters. The printing wires of devices 58 are heated by means of a heating coil 59 disposed around the wires. As the heated wires of device 58 are selectively positioned to form the different characters, they contact the portion 42" to produce heating of the surface in accordance with the configuration of the particular combination of wires. This heating expands and fixes the bubbles produced by the prior irradiation to produce on card 41 a permanent image corresponding to the configuration of the heated printing wires. Card 41" thus has at the end of its processing a plurality of images of the documents from film 46 on portion 43", together with a representation on portion 42" indicating the nature of the images stored on portion 43".

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to the preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, Without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claim.

What is claimed is:

A method of printing on a sheet of vesicular material containing a binder impregnated with a light sensitive diazonium salt which decomposes when exposed to light to evolve nitrogen gas in the form of small bubbles and which forms a multiplicity of larger, light scattering bubbles upon application of heat to said liberated nitrogen gas bubbles, comprising the steps of irradiating with light an area of said sheet of vesicular material to liberate said nitrogen gas bubbles over substantially the said entire area and contacting the thus irradiated area of said sheet with the heated raised portions of a printing element, the configuration of which corresponds to the informationto be printed, thus to produce a multiplicity of said light refractive bubbles where said sheet of vesicular material is contacted by the heated, raised portions of said printing element.

References Cited in the file of this patent UNITED STATES PATENTS 

